English Etymology From semi- + postal. Adjective semipostal (not comparable) (of a postage stamp) Issued and sold for a higher price than its face value, with the excess monies transferred to a third party, typically a charity. Translations issued and sold for higher price than face value Finnish: avustus- (fi) Further reading semipostal on Wikipedia.Wikipedia Noun semipostal (plural semipostals) A postage stamp of this kind. Synonyms semi-postal stamp, charity stamp Translations type of stamp — see semi-postal stampWikiwand - on Seamless Wikipedia browsing. On steroids.